Flash memory and manufacturing method thereof as well as formation method of grids in different thicknesses

Abstract

The invention provides a manufacturing method of a separate grid type flash memory used for an embedded logic circuit. Compared with a formation method of an individual separate grid type flash memory, the manufacturing method provided by the invention has the advantage that the separate grid type flash memory, a high voltage transistor and a logic transistor can be manufactured on one integrated circuit at the same time only by realizing formation of the grids in different thicknesses in an embedded separate grid type flash memory by virtue of chemical mechanical milling on two-layer polycrystalline silicon and oxidation of polycrystalline silicon, so that densities of the separate grid type flash memory, the high voltage transistor and the logic transistor can be increased, integration degree is high, operating speed is higher, and an integrated chip is smaller, so that cost of the whole integrated chip is reduced. The invention also provides a separate grid type flash memory used for the embedded logic circuit and a method for forming the grids in different thicknesses.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to an embedded split-gate flash memory, a manufacturing method thereof, and a method for forming gates with different thicknesses. Background technique [0002] Random access memory, such as DRAM and SRAM, has the problem of data loss after power failure during use. To overcome this problem, various embedded split-gate flash memories have been designed and developed. Recently, flash memory based on floating gate concept has become the most common embedded split-gate flash memory due to its small cell size and good working performance. [0003] Among them, a split-gate flash memory transistor is constructed as figure 1 , including a split gate structure and an erasable gate 1 between two adjacent split gate structures, and word lines 2 respectively located on the sides of the two split gate structures away from each other. Wherein, the split gate structure includes a flo...

AI Technical Summary

Problems solved by technology

[0005] Generally speaking, flash memory, high-voltage transistors, and logic transistors are separately built on discrete integrated chips. In this way, the operating speed of the entire memory will be limited by the signal transmission bandwidth between the flash memory and peripheral circuits.

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